D-Day is important for World War II because it was the main Allied invasion of continental Europe. It was this invasion that allowed the Allies to finally defeat Germany.

In order for the Allies to defeat Germany, there would have to be an invasion of Europe. The Western Allies did invade through Italy, but this was not a very promising route to actually invade Germany. In order to truly attack Germany, the Allies would have to invade in the North. This is what happened on D-Day. D-Day was the Allied invasion that allowed the Western Allies to attack and (with major help from Soviet pressure from the East) finally defeat Germany.

D-Day, or 'Deliverance Day' , 6th June 1944, was, as pointed out above by pohnpei397, the day of the allied 'riposte' or counter-invasion of German-occupied Europe (via the Normandy/French landings chiefly) which finally led to Germany's defeat.

World War II took place between 1939 and 1945 between the Axis Powers (Germany, Japan, Italy) and the Allied Powers (US, Soviet Union, Great Britain, France, China).

Among the causes of the war were unsettled disputes from World War I and the growing power of Nazi Germany. For the US, the attack on Pearl Harbor was a major factor in the decision to enter the war.

D-Day is another name for the invasion of Normandy in which the Allied forces attacked the German forces in a place called Normandy on the coast of France on June 6, 1944. There were some 156,000 Allied troops that invaded that day. It was a turning point in the war.

"D-Day" is a military term meaning the day of a major military attack. The other name for the invasion of Normandy was "Operation Overlord." The Allied forces were victorious in this very important battle. The victory at Normandy is believed to have been "the beginning of the end of World War II." It was a huge success for the Allied forces. Had the result at Normandy been different, the result of the entire war could have been different.

More than 4,000 Allied troops died on D-Day.

There are many films which have taken this famous invasion as their topic, the 1998 film Saving Private Ryan being one of the most popular.

D-day refers to the allied forces' invasion at Normandy on June 6, 1944 during World War II. It is widely regarded as the single most important event in WWII and led to its conclusion in Europe. It resulted in the freedom of France. This invasion helped allied forces open a western front, which the Soviet Union had been demanding for a long time. This front, initially started at Normandy Beach, was continually expanded in the coming months with the landing of more allied troops. This new front led to the division of the German forces, who were also battling Soviet Union forces on the eastern front and were in retreat after the loss of the Battle of Stalingrad. The weakened German forces were easily defeated and finally the tide was decisively turned in favor of the allied forces, thus making D-day the cornerstone of WWII.